1. Field
The present disclosure relates to a light emitting diode, and a method of manufacturing the same, and particularly, to a silicon nano crystal light emitting diode, and a method of manufacturing the same.
2. Description of the Related Art
When silicon has a nano-size, an energy band structure may have a direct transition type band structure, which is similar to an energy band structure of a compound semiconductor. Since a silicon nano crystal has the direct transition type band structure, it is possible to manufacture a highly efficient light source by using a quantum confinement effect of the silicon nano crystal.
In general, the silicon nano crystal is formed within a silicon oxide layer (SiOx). However, when the silicon oxide layer is used for forming the silicon nano crystal, a heat treatment at a high temperature exceeding 1,000° C. needs to be essentially performed. Further, since interfacial defects are generated between the silicon oxide layer and the silicon nano crystal, it is difficult to manufacture a highly efficient light source and a light source having various wavelengths within a visible ray region through the silicon nano crystal formed within the silicon oxide layer.
In the meantime, when a silicon nitride layer SiNx is used for forming the silicon nano crystal, it is possible to simultaneously form the silicon nano crystal within the silicon nitride layer when the silicon nitride layer is grown. Accordingly, when the silicon nano crystal is formed by using the silicon nitride layer, a heat treatment at a high temperature is not required. Further, since the silicon nitride layer has a small energy band gap than that of the silicon oxide layer, it is easy to inject a current into a photoelectric conversion layer including a nano crystal from an external electrode. Further, since a defect between an interface between the silicon nitride layer and the silicon nano crystal is small, a loss of electrons and holes is small, thereby manufacturing a highly-efficient light source. As described above, the light source using the silicon nano crystal formed within the silicon nitride layer has various advantages, so that research on the light source has been actively conducted.
In general, when a silicon nano crystal light emitting diode is fabricated, the photoelectric conversion layer including the silicon nano crystal is grown on a silicon substrate. Further, a wavelength region of light emitted from the silicon nano crystal light emitting diode has a wavelength band of a visible ray region. Most of the light having a wavelength in a visible ray region emitted from the photoelectric conversion layer of the silicon nano crystal light emitting diode is absorbed in the silicon substrate, so that there is a disadvantage in that light efficiency of the light emitting diode deteriorates. Accordingly, a method of effectively extracting light generated within the photoelectric conversion layer including the silicon nano crystal to the outside of the diode has been demanded.